Internal combustion engines are widely used in a variety of handheld tools such as, but not limited to, chainsaw, hedge trimmer, grass trimmer, blower, mower, and the like. The engine driven handheld tools are provided with a tank such as a fuel tank or a lubricant tank with a refill opening. Typical closure device for the threaded fill opening of the tank may include a threaded cap which is engageable with the corresponding threads in the refill opening. The threaded cap closes off the refill opening tightly with respect to the ambient by tightening the cap in the refill opening.
Most of the conventional closure devices provide an unfavorable grip to an operator. Also, a portion of the cap that protrudes outwardly when the cap is in the closed position is used for gripping by the operator. Moreover, caps with an openable gripping portion are also used in the handheld tools. The openable gripping portion may be opened to provide a better grip to the operator while releasing or tightening of the cap. These caps may be better than the conventional caps, however, they suffer from the problem of unintended opening of the openable gripping portion. The unintended opening of the openable gripping portion may result in breaking of the cap or unintended releasing of the cap.
Therefore, there exists a need for a closure device for a tank such as, but not limited to, a fuel tank or a lubricant tank of the handheld tool. Moreover, there exists a need for the closure device which provides a better grip to an operator while releasing or tightening of a cap.